I finally found an answer to my question regarding Robert McNairy and Albina Johnson. W. Thomas Carden wrote and published articles titled, PISGAH [Giles County, TN] HISTORY, Nov 24, 1904 article.
[In regards to activities at the Mt. Pisgah [religious] Camp Meetings] "One marriage, a Gretna Green affair created a furor.It took place in one of the tents.The contracting parties was Robert McNairy and Albina "Duck" Johnson.The bride a niece and ward of Wm H. Oliver."
Wm. Hugh Oliver was the younger brother of Charlotte Caroline Oliver, the wife of James M. Johnston/Johnson.Albina's parents appear to have died prior to the 1850 census.
As for Robert McNairy a court order in Giles County, TN records: 17 Jan 1850 - Court ordered that Ananias Oliver be appointed guardian of Robert, Francis, Marcus, Wm. J. McNairy, orphans of Francis L. Mc Nairy, in the place of Daniel Leatherman.
Ananias Oliver was the older brother of William Hugh Oliver, guardian of Albina Johnson, the future wife of the above Robert.
Francis L. McNairy, dec'd 1850 was the son of Robert McNairy, dec'd 1830 Giles County and grandson of John McNairy.